Damper assemblies for engine disconnect clutches of motor vehicle powertrains

ABSTRACT

Disclosed are damper assemblies for engine disconnect devices, methods for making such damper assemblies, and motor vehicles with a disconnect device for coupling/decoupling an engine with a torque converter (TC). A disconnect clutch for selectively connecting an engine with a TC includes a pocket plate that movably mounts to the TC. The pocket plate includes pockets movably seating therein engaging elements that engage input structure of the TC and thereby lock the pocket plate to the TC. A selector plate moves between engaged and disengaged positions such that the engaging elements shift into and out of engagement with the TC input structure, respectively. A flex plate is attached to the engine&#39;s output shaft for common rotation therewith. A damper plate is attached to the pocket plate for common rotation therewith. Spring elements mate the damper and flex plates such that the damper plate is movably attached to the flex plate.

INTRODUCTION

The present disclosure relates generally to motor vehicle powertrains.More specifically, aspects of this disclosure relate to disconnectdevices for operatively disengaging internal combustion engines fromtorque converters.

Current production motor vehicles, such as the modern-day automobile,are originally equipped with a powertrain that operates to propel thevehicle and power the onboard vehicle electronics. In automotiveapplications, the powertrain is generally typified by a prime mover thatdelivers driving power to the vehicle's final drive system (e.g., reardifferential, axle, and wheels) through a manually or automaticallyshifted multi-speed power transmission. Automobiles have traditionallybeen powered by a reciprocating-piston type internal combustion engine(ICE) assembly because of its ready availability and relativelyinexpensive cost, light weight, and overall efficiency. Such enginesinclude compression-ignited (CI) diesel engines, spark-ignited (SI)gasoline engines, two, four and six-stroke architectures, and rotaryengines, as some non-limiting examples. Hybrid and full-electricvehicles, on the other hand, utilize alternative power sources to propelthe vehicle and minimize/eliminate reliance on an engine for power.

Hybrid vehicle powertrains utilize multiple traction power sources topropel the vehicle, such as an ICE assembly operating in conjunctionwith a battery-powered or fuel-cell-powered motor. A hybrid electricvehicle (HEV), for example, stores both electrical energy and chemicalenergy, and converts the same into mechanical power to drive thevehicle's road wheels. The HEV is generally equipped with an electricmachine (E-machine), such as one or more electric motor/generators, thatoperate in parallel or in series with an internal combustion engine.Since hybrid vehicles are designed to derive their power from sourcesother than the engine, engines in HEVs may be turned off, in whole or inpart, while the vehicle is propelled by the alternative power source(s).A full electric vehicle (FEV)—colloquially known as “all-electric”vehicles—is an alternative type of electric-drive vehicle configurationthat altogether eliminates the internal combustion engine and attendantperipheral components from the powertrain system, relying solely onelectric tractive motors for vehicle propulsion.

Vehicle powertrains employing an automatic transmission commonlyinterpose a hydrodynamic torque converter between the internalcombustion engine and the multi-speed transmission to govern thetransfer of rotational torque therebetween. Replacing the mechanicalclutch of a manual transmission, a standard torque converter includes afluid impeller that is coupled to the engine's output shaft, a turbinethat is coupled to the transmission's input shaft, and a statorinterposed between the impeller and turbine to regulate fluid flowbetween their respective fluid volumes. A hydraulic pump modulateshydraulic fluid pressure within the torque converter housing to regulatethe transfer of rotational energy from the impeller to the turbine.Hydraulic fluid may be bled from the housing to increase slip orotherwise operatively disengage the engine crankshaft from thetransmission input shaft and to multiply torque (e.g., function as apseudo-reduction gear) to offset significant differences between inputand output speeds.

A torque converter (TC) may generally be typified as a fluid couplingthat allows the engine to selectively transmit power to the drivetrainsystem for vehicle propulsion, and allows the crankshaft to spin—withoutthe engine stalling—when the vehicle wheels and transmission gears cometo a stop. For instance, if the engine is rotating slowly, e.g., whenthe vehicle is braking to a stop or idling at a stop light, hydraulicpressure between the impeller and turbine is reduced such that theamount of torque passed through the torque converter to the transmissionis very small. In so doing, the vehicle may be kept still with lightpressure on the brake pedal. To accelerate the vehicle, the TC pumpincreases internal fluid pressure, thereby causing increased amounts oftorque to be transmitted from the impeller through the turbine to thetransmission for launching the vehicle. For manual transmissions, thetorque converter is typically replaced with a driver-operated clutchengaged and disengaged by a foot pedal.

Some torque converters are equipped with a clutch mechanism thatfunctions to rigidly connect the engine crankshaft to the transmissioninput shaft when their speeds are nearly equal, e.g., to avoid unwantedslippage and resultant efficiency losses. System “slip” occurs becausethe rotational speed of the impeller relative to the turbine in thetorque converter is inherently different. A large slip percentagebetween the engine output and the transmission input affects the fueleconomy of the vehicle; employing a torque converter clutch (TCC) helpsto reduce the slip between the engine and the transmission. The TCCoperates to mechanically lock the impeller at the output of the engineto the turbine at the input of the transmission so that the engineoutput and transmission input rotate at the same speed. Application ofthe TCC may be controlled by an electronic controller to modify clutchengaging forces under certain operating conditions, for example, duringshifts to eliminate undesired torque fluctuations and engine speedchanges during transient periods when torque flow interruption isdesired.

SUMMARY

Disclosed herein are damper assemblies for engine disconnect devices,methods for making and methods for operating such damper assemblies, andmotor vehicles equipped with an internal combustion engine that isoperatively coupled to/decoupled from a hydrokinetic torque convertervia an intermediate disconnect device with a damper assembly. By way ofexample, and not limitation, there is presented a novel enginedisconnect clutch with torsional damper assembly that is disposedbetween the engine output and the torque converter input. In a morespecific example, a positive-engagement selectable one-way clutch (SOWC)is placed between the engine crankshaft and torque converter pump. TheSOWC includes a tuned-spring damper assembly fabricated with a flexplate that is mechanically coupled to the crankshaft upstream from theSOWC's clutching mechanism. Damping springs mechanically engage the flexplate with a damper plate of the damper assembly. This damper plate ismechanically coupled, e.g., via circumferentially spaced bolts, to apocket plate of the SOWC. The pocket plate, in turn, is rotatablymounted on the TC pump housing and includes engaging elements, such asrotatable pawls, sprags, rollers, needles, etc., that operatively engagethe TC pump housing to thereby lock the pocket plate to the torqueconverter for common rotation therewith. A coaxially aligned selectorplate adjacent the pocket plate is rotated to selectively engage anddisengage the engaging elements from the TC pump housing. For thisexample, the damper assembly may be packaged in an unlubricated volumeand, thus, designed to run dry.

Attendant benefits for at least some of the disclosed features includean engine disconnect device with torsional damper assembly that helps todiminish torque swings, e.g., below zero for positive torque, to therebyminimize vehicle noise, vibration and harshness (NVH) that can resultfrom backlash during torque reversals. Aspects of the disclosed conceptsalso help to reduce the impact velocity and other related effects oftorque reversals on a SOWC. Disclosed engine disconnect damper assemblydesigns may also reduce the required travel of the damping elements soas to minimize the overall size and requisite packaging space for thedamper assembly. Disclosed disconnect devices and damper assemblies canbe incorporated into both manual and automatic transmissionarchitectures.

Aspects of the present disclosure are directed to controllable enginedisconnect devices for selectively connecting and disconnecting aninternal combustion engine assembly with a hydrokinetic torqueconverter. Disclosed, for example, is a disconnect clutch forselectively connecting an engine assembly with a torque converter. Thedisconnect clutch includes a pocket plate that movably attaches to thetorque converter, e.g., rotatably mounted on the TC pump cover. Thispocket plate includes a series of pockets, e.g., circumferentiallyspaced along the perimeter of the pocket plate. A plurality of engagingelements, which may be in the nature of pawls, sprags, rollers, etc.,engage the pockets with the input structure to thereby lock the pocketplate to the torque converter for common rotation therewith. In anexample, each engaging element is a spring-biased pawl rotatably seatedin a respective one the pocket plate pockets. Alternatively, theengaging elements may be movably attached to the TC and operable toengage and disengage the pockets in the pocket plate.

A selector plate, which is packaged adjacent the pocket plate,selectively moves between engaged and disengaged positions. When theselector plate is in the engaged position, the engaging elements engageand thereby lock together the pocket plate and the torque converter.Conversely, when moved to the disengaged position, the selector plateshifts the engaging elements out of engagement between the pockets andinput structure such that the pocket plate can move with respect to theTC. A flex plate packaged adjacent one side of the pocket plate attachesto an output shaft of the engine assembly for common rotation therewith.A damper plate, which is adjacent the flex plate on the opposite side ofthe pocket plate, e.g., interposed between the flex plate and engineassembly, is attached to the pocket plate for common rotation therewith.Spring elements, which may be sandwiched between the damper plate andpocket plate, mate the damper plate with the flex plate such that thedamper and pocket plates are movably attached to and spring-biased withthe flex plate.

Other aspects of the present disclosure are directed to motor vehiclesequipped with a reciprocating-piston-type internal combustion engineassembly operatively connected to a multi-speed power transmission by ahydrokinetic torque converter. A “motor vehicle,” as used herein, mayinclude any relevant vehicle platform, such as passenger vehicles (ICE,hybrid, fuel cell, fully or partially autonomous, etc.), commercialvehicles, industrial vehicles, tracked vehicles, off-road andall-terrain vehicles (ATV), farm equipment, boats, airplanes, etc. Amotor vehicle is presented that includes a vehicle body with an enginecompartment, and an ICE assembly mounted inside the engine compartment.The ICE assembly includes a crankshaft for outputting torque generatedby the ICE assembly to the vehicle drivetrain. A multi-speedtransmission receives, selectively modifies, and transmits torque outputby the ICE assembly to one or more of the vehicle's drive wheels. Ahydrodynamic torque converter selectively connects the ICE assembly tothe multi-speed transmission to govern the transfer of torquetherebetween.

Continuing with the above example, the motor vehicle also includes aselectable one-way clutch with a pocket plate that is movably mounted toan exterior portion of the torque converter. This pocket plate includesa series of pockets spaced about the pocket plate. Engaging elementsselectively engage the pockets with input structure of the torqueconverter to thereby lock the pocket plate to the TC for common rotationtherewith. A selector plate, which is located adjacent the pocket plate,moves between an engaged position, whereat the engaging elements shiftinto engagement between the pockets and the TC input structure, and adisengaged position, whereat the selector plate shifts the engagingelements out of engagement such that the pocket plate freewheels on theexterior of the torque converter. A flex plate interposed between thepocket plate and ICE assembly is rigidly attached to the engine'scrankshaft for common rotation therewith. A damper plate interposedbetween the flex plate and ICE assembly is rigidly attached to thepocket plate for common rotation therewith. Spring elements, which maybe in the nature of helical, leaf, torsional, or other spring types,mate the damper plate with the flex plate such that the damper andpocket plates are movably attached to the flex plate.

Additional aspects of the present disclosure are directed to methods formaking and methods for assembling any of the disclosed engine disconnectdevices and corresponding damper assemblies. Aspects of the presentdisclosure are also directed to methods for operating disclosed enginedisconnect devices and damper assemblies. Also presented herein arenon-transitory, computer readable media storing instructions executableby at least one of one or more processors of one or more in-vehicleelectronic control units, such as a programmable engine control unit(ECU) or powertrain control module, to govern operation of a disclosedengine disconnect device.

The above summary is not intended to represent every embodiment or everyaspect of the present disclosure. Rather, the foregoing summary merelyprovides an exemplification of some of the novel aspects and featuresset forth herein. The above features and advantages, and other featuresand advantages of the present disclosure, will be readily apparent fromthe following detailed description of illustrative embodiments andrepresentative modes for carrying out the present disclosure when takenin connection with the accompanying drawings and the appended claims.Moreover, this disclosure expressly includes any and all combinationsand subcombinations of the elements and features presented above andbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a representative motor vehiclewith a powertrain having a final drive system drivingly connected to anengine assembly by a multi-speed power transmission in accordance withaspects of the present disclosure.

FIG. 2 is a cross-sectional side-view illustration of select portions ofa representative hydrodynamic torque converter, engine disconnectclutch, and torsional damper assembly in accordance with aspects of thepresent disclosure.

FIG. 3 is a partially exploded perspective-view illustration of therepresentative hydrodynamic torque converter, engine disconnect clutch,and torsional damper assembly of FIG. 2.

FIG. 4 is an enlarged front-view illustration of a representative flexplate with integrally formed damper leaf springs in accord with aspectsof the disclosed concepts.

The present disclosure is amenable to various modifications andalternative forms, and some representative embodiments have been shownby way of example in the drawings and will be described in detailherein. It should be understood, however, that the novel aspects of thisdisclosure are not limited to the particular forms illustrated in theappended drawings. Rather, the disclosure is to cover all modifications,equivalents, combinations, subcombinations, permutations, groupings, andalternatives falling within the scope of this disclosure as defined bythe appended claims.

DETAILED DESCRIPTION

This disclosure is susceptible of embodiment in many different forms.There are shown in the drawings and will herein be described in detailrepresentative embodiments of the disclosure with the understanding thatthese illustrated examples are to be considered an exemplification ofthe disclosed principles and do not limit the broad aspects of thedisclosure to the representative embodiments. To that extent, elementsand limitations that are disclosed, for example, in the Abstract,Summary, and Detailed Description sections, but not explicitly set forthin the claims, should not be incorporated into the claims, singly orcollectively, by implication, inference or otherwise. For purposes ofthe present detailed description, unless specifically disclaimed: thesingular includes the plural and vice versa; the words “and” and “or”shall be both conjunctive and disjunctive; the word “all” means “any andall”; the word “any” means “any and all”; and the words “including” and“comprising” and “having” and synonyms thereof mean “including withoutlimitation.” Moreover, words of approximation, such as “about,”“almost,” “substantially,” “approximately,” and the like, may be usedherein in the sense of “at, near, or nearly at,” or “within 3-5% of,” or“within acceptable manufacturing tolerances,” or any logical combinationthereof, for example.

Referring now to the drawings, wherein like reference numbers refer tolike features throughout the several views, there is shown in FIG. 1 aschematic illustration of a representative automobile, which isdesignated generally at 10 and portrayed herein for purposes ofdiscussion as a passenger vehicle with a two-clutch parallel (P2)hybrid-electric powertrain. In particular, the illustrated powertrain isgenerally composed of a single engine 12 and a single motor 14 thatoperate, individually or in concert, to transmit tractive power to amulti-speed power transmission 16 through a hydrokinetic torqueconverter 18 to drive one or more drive wheels 20 of the vehicle'sdrivetrain 11. The illustrated automobile 10—also referred to herein as“motor vehicle” or “vehicle” for short—is merely an exemplaryapplication with which novel aspects and features of this disclosure canbe practiced. In the same vein, implementation of the present conceptsinto a P2 hybrid-electric architecture should also be appreciated as anexemplary application of the novel concepts disclosed herein. As such,it will be understood that aspects and features of the presentdisclosure can be applied to other vehicle powertrain configurations andutilized for any logically relevant type of motor vehicle. Lastly, onlyselect components of the vehicle have been shown and will be describedin additional detail herein. Nevertheless, the vehicle and powertraincomponents discussed below can include numerous additional andalternative features, and other well-known peripheral components, e.g.,for carrying out the various methods and functions of this disclosure.

The representative vehicle powertrain system is shown in FIG. 1 with aprime mover, such as a restartable internal combustion engine (ICE)assembly 12 that is drivingly connected to a driveshaft 15 of a finaldrive system 11 by a multi-speed automatic power transmission 16. Theengine 12 transfers power, preferably by way of torque via an enginecrankshaft 13, to an input side of the transmission 16. As shown, theprime mover 12 directly drives a damper 26 which, in turn, directlydrives an engine disconnect device 28. When operatively engaged, theengine disconnect device 28 transmits torque received from the ICE 12 byway of the damper 26 to input structure of the TC 18. The transmission16, in turn, is adapted to receive, manipulate and distribute power fromthe engine 12 to the final drive system 11—represented herein by a reardifferential 22 and a pair of rear drive wheels 20—and thereby propelthe hybrid vehicle. In the example depicted in FIG. 1, the ICE assembly12 may be any available or hereafter developed engine, such as a 2 or4-stroke compression-ignited diesel engine or a 4-stroke spark-ignitedgasoline or flex-fuel engine, which is readily adapted to provide itsavailable power output typically at a number of revolutions per minute(RPM). Although not explicitly portrayed in FIG. 1, it should beappreciated that the final drive system 11 may comprise any availableconfiguration, e.g., front wheel drive (FWD), rear wheel drive (RWD),four-wheel drive (4WD), all-wheel drive (AWD), etc.

FIG. 1 also displays an electric motor/generator assembly 14 or otherE-machine that operatively connects to a main shaft 17 of theelectro-hydraulic transmission 16 via the torque converter 18. Themotor/generator 14 can be directly coupled onto a TC input shaft 19 orsplined housing portion (e.g., front cover 38 of FIG. 2) of the torqueconverter 18 via one or more selectively engageable torque transmittingmechanisms 24 (e.g., clutch, brake, etc.). The electric motor/generator14 is composed of an annular stator 21 circumscribing and concentricwith a rotor 54. Electric power is provided to the stator 21 throughelectrical conductors or cables 23 that pass through the motor housingin suitable sealing and insulating feedthroughs (not illustrated).Conversely, electric power may be provided from the motor 14 to anonboard traction batter pack 30 via regenerative braking. Operation ofany of the illustrated powertrain components may be governed by anonboard or remote vehicle controller, such as programmable electroniccontrol unit (ECU) 25. While shown as a P2 hybrid-electric architecturewith a single motor in parallel power-flow communication with a singleengine assembly, the vehicle 10 may employ other powertrainconfigurations, including PS, P1, P3, and P4 hybrid powertrains, any ofwhich may be adapted for an REV, BEV, plug-in, range-extended, orfuel-cell vehicle, as well as full-electric and standard ICEpowertrains.

Control module, module, control, controller, control unit, processor andsimilar terms mean any one or various combinations of one or more ofApplication Specific Integrated Circuit(s) (ASIC), electroniccircuit(s), central processing unit(s) (e.g., microprocessor(s)), andassociated memory and storage (read only, programmable read only, randomaccess, hard drive, etc.) executing one or more software or firmwareprograms or routines, combinational logic circuit(s), input/outputcircuit(s) and devices, appropriate signal conditioning and buffercircuitry, and other components to provide the described functionality.Software, firmware, programs, instructions, routines, code, algorithmsand similar terms mean any controller executable instruction setsincluding calibrations and look-up tables. The ECU can be designed witha set of control routines executed to provide the desired functions.Control routines are executed, such as by a central processing unit, andare operable to monitor inputs from sensing devices and other networkedcontrol modules, and execute control and diagnostic routines to controloperation of devices and actuators. Routines may be executed at regularintervals, for example each 100 microseconds (μs), 3.125, 6.25, 12.5, 25and 100 milliseconds during ongoing engine and vehicle operation.Alternatively, routines may be executed in response to occurrence of anevent.

FIG. 2 is a cross-sectional side-view illustration of a portion of arepresentative torque converter assembly 18. Hydrokinetic torqueconverter assembly 18 is a fluid coupling for operatively connecting anddisconnecting the ICE assembly 12 and electric motor/generator assembly14 with/from the internal epicyclic gearing of the power transmission16. As shown in FIG. 2, the torque converter assembly 18 is generallycomprised of a torque converter impeller 32, a bladed turbine 34, and arelatively stationary stator 36. To protect these components, the torqueconverter assembly 18 is constructed with an annular housing, definedprincipally by an engine-side front cover 38 (also referred to herein as“pump housing”) fixedly attached, e.g., via electron beam welding, MIGor MAG welding, laser welding, and the like, to a transmission-side pumpshell portion 40 such that a working hydraulic fluid chamber is formedtherebetween. The impeller 32—also referred to in the art as “pump”—issituated in serial power-flow fluid communication with the turbine 34.

Interposed between the impeller 32 and turbine 34 is a stator 36 thatselectively alters fluid flow returning from the turbine 34 to theimpeller 32 such that returning fluid aids, rather than impedes,rotation of the impeller 32. The transfer of engine torque from thecrankshaft 13 to the turbine 34, via the annular housing front cover 38and impeller 32, is through the operation of hydraulic fluid, such astransmission oil in the TC fluid chamber. More specifically, rotation ofimpeller blades 37, retained between the pump shell 40 and an innershroud 42, causes the hydraulic fluid to be directed toroidally outwardtoward the turbine 34. When this occurs with sufficient force toovercome the inertial resistance to rotation, turbine blades 39, whichare coaxially oriented with the impeller blades 37 and retained betweenthe inner shroud 42 and a turbine shell 41, begin to rotate with theimpeller 32. The fluid flow exiting the turbine 34 is directed back intothe impeller 32 by way of the stator 36. The stator 36, located betweenthe flow exit section of the turbine 34 and the flow entrance section ofthe impeller 32, redirects the fluid flow from the turbine 34 to theimpeller 32 in the same direction as impeller rotation, thereby reducingpump torque and causing torque multiplication.

The stator 36 of FIG. 2 may be connected to a stator shaft 44 by way ofa roller clutch 46 that is operable to prevent rotation of the stator 36at low torque converter speeds. At higher torque converter speeds, thedirection of hydraulic fluid leaving the turbine 34 changes, causing thestator 36 to over-run the roller clutch 46 and rotate freely on thestator shaft 44. The impeller 32 is secured to a pump hub 48, whereasthe turbine 34—namely turbine blades 39 and turbine shell 41—isrotatably mounted onto a TC output shaft 50. As shown, a turbine hub 52is disposed between, and configured to operatively couple together theturbine 34 and the TC output shaft 50. The turbine hub 52 is shownsecured to the turbine shell 41, for example, by a series of rivets, andengages the TC output shaft 50, for example, by a splined interface

Fundamentally, as the internal combustion engine 12 turns off to on, onto off, and operates at different rotational speeds during transientmodes, it may produce torque-related vibrations and oscillations(colloquially known as “torsionals”). By way of example, when fuel isbeing fed to the engine 12 and it is under power, e.g., throughengagement of the fuel throttle (not shown herein) during normaloperation, the engine 12 may produce torsionals that are undesirable totransmit to, and through the transmission 16. In addition, when theengine 12 is not being fueled or is not under power (e.g., in a startupand/or a shutdown operation), the engine pistons may generatecompression pulses. Both the torsionals and compression pulses canproduce resultant vibrations, noise and rattle that may be sensed by avehicle occupant. To help reduce or otherwise cancel out the torsionals,torque swings and compression pulses that may be produced by the engine12, the vehicle 10 is equipped with an engine disconnect damper assembly26, as shown in FIGS. 1-3. As will be described in detail below, thedamper assembly 26 generally functions to isolate the torque converter18 and, thus, the transmission 12 from unwanted torsionals generated bythe engine 12, and also to selectively aide the motor/generator assembly14 in canceling engine compression pulses during startup and shutdownoperations.

According to the representative example illustrated in FIGS. 2 and 3,the engine disconnect device 28 is generally comprised of a pocket plate60, a selector plate 62, and a selector ring 64 that is generallyinterposed between and concentrically aligned with the pocket andselector plates 60, 62. In the same vein, the damper assembly 26 ofFIGS. 2 and 3 is generally comprised of a flex plate 66 and a damperplate 68, with the flex plate 66 interposed between and concentricallyaligned with the pocket and damper plates 60, 68. The pocket plate 60 isa disk-shaped annulus that movably attaches and, when desired,selectively locks the engine disconnect device 28 and, indirectly, thedamper assembly 26 to the torque converter 18. By way of non-limitingexample, the TC pump housing 38 is integrally formed with a generallycylindrical hub portion 31 that projects orthogonally from a disk-shapedflange portion 33. Pocket plate 60 can be seen in FIG. 2 rotatablymounted onto the hub portion 31 of the pump housing 38 such that thetorque converter 18 and engine disconnect device 28 are coaxiallyaligned to both rotate about axis A-A. To operatively align and retainthe pocket plate 60, the TC pump housing 38 may be fabricated with anannular slot 35 that extends continuously around the outer periphery ofthe hub portion 31; an inner periphery of the pocket plate 60 isprovided with a central ring 61 that concentrically aligns with andslidably seats within the this annular slot 35.

Engine disconnect device 28 is portrayed herein for purposes ofdiscussion as a positive-engagement, pawl-type selectable one-way clutch(SOWC). Alternatively, the engine disconnect device 28 may take on otheravailable constructions, such as selectable roller or needle clutches,controllable mechanical diode clutches, and sprag clutch designs, as afew non-limiting examples. This disclosure contemplates that otherselectable, reversible and multi-mode torque transmitting devices couldbe used to effectuate the features of the present disclosure. Pocketplate 60 of FIG. 3, for example, is fabricated with a sequence ofcircumferentially spaced pockets 63 (one of which is visible in FIG. 2)that are recessed into an aft-facing, transmission-side surface of theplate 60. Each pocket 63 movably nests therein a respective engagingelement that functions to engage with torque-receiving input structureof the torque converter 18, and cooperatively lock the pocket plate 28to the torque converter 18 such that the two rotate in unison. Accordingto the representative architecture of FIGS. 2 and 3, each engagingelement is composed of a spring-biased pawl 70 that is rotatably seatedwithin a respective one of the aforementioned pockets 63. Each pawl 70is provided with a respective biasing member 72, which can be a torsionspring, a coil spring, constant force spring, or any other elementcapable of providing lift to one end of the engaging element.

The torque-receiving input structure of the torque converter 18 isgenerally comprised of circumferentially spaced notches 27 that areindividually recessed into the engine-side, fore-facing surface of thepump housing's flange portion 33. This series of notches 27 is radiallyaligned with the pockets 63 in the pocket plate 60, each shaped andsized to receive therein a pawl 70. The pawls 70 engage the pump housing38—thereby locking the pocket plate 60 to the torque converter 18 forcommon rotation therewith—by protruding rearward (leftward in FIGS. 2and 3) into and pressing against the notches 27. Conversely, the pawls70 selectively disengage the pump housing 38—thereby unlocking thepocket plate 60 from the torque converter 18 to freewheel thereon—byreceding into their respective pockets 63 out of contact with thenotches 27. It will be apparent that the number, arrangement andgeometry of the engaging elements 70 and their corresponding pockets 27can be varied from that which are shown in the drawings depending, forexample, on design requirements for the intended application.

To govern the operating status of the engine disconnect device 28 and,thus, the torque-transmitting mechanical coupling between the engineassembly 12 and torque converter 18, the disconnect device 28 isprovided with a selector plate 62 and selector ring 64 thatcooperatively control the engagement and disengagement of the pawls 70with/from the TC pump housing 38. The selector plate 62 is a disk-shapedannulus neighboring the pocket plate 62 and coaxially aligned with thetorque converter 18 and damper assembly 26 on axis A-A. This selectorplate 62 is mounted for rotational movement relative to the pocket plate60 to transition back-and-forth between an engaged and a disengagedposition. When the selector plate 62 is in its engaged position, theengaging elements 70 of the pocket plate 60 are allowed to shift intoengagement with the input structure of the torque converter 18, e.g.,under the biasing force of the biasing members 72. On the other hand,when the selector plate 62 rotates (e.g., counterclockwise in FIG. 3) toits disengaged position, the plate 62 presses or otherwise shifts theengaging elements 70 out of engagement with the TC input structure. Byway of example, and not limitation, the selector plate 62 is machinedwith a series of circumferentially spaced windows 65, each of which isshaped and sized to receive therethrough a portion of a single pawl 70.Moving the selector plate 62 to the engaged position aligns the windows65 with corresponding pockets 63 such that the pawls 70 seated thereinproject through the windows 65 and into the notches 27 of the pumphousing 38.

The selector ring 64 of FIGS. 2 and 3 is a disc-shaped component with acentrally located cylindrical hub 67 that is sized to circumscribe andseat therein the SOWC pocket plate 60. When the engine disconnect device28 is fully assembled, an aft-facing, transmission-side surface of theselector ring 64 sits generally flush against a forward-facingengine-side surface of the selector plate 62, while an inner-diametersurface of the central hub 67 sits generally flush with an outerperiphery surface of the pocket plate 60, as best seen in FIG. 2.Circumferentially spaced tabs 69 project from the selector plate 62 intocomplementary slots in the selector ring 64 to operatively interconnectthe two components such that they rotate in unison. A selectivelyengageable brake mechanism 76 (FIG. 2) is activated by a vehiclecontroller, such as ECU 25 of FIG. 1, to restrict rotational motion ofthe selector ring 64 about axis A-A. In so doing, the ring 64 isselectively transitioned back-and-forth from between deactivated andactivated positions to thereby move the selector plate 62 between theengaged and disengaged positions, respectively.

An engine flex plate 66, which is immediately adjacent both the pocketplate 60 and damper plate 68 (effectively sandwiched therebetween),mechanically attaches the damper assembly 26 and, indirectly, the enginedisconnect device 28 to the torque-transmitting output of the engineassembly 12. According to the representative architecture illustrated inFIGS. 2 and 3, the ICE assembly 12 is equipped with an engine hub 74that is rigidly mounted to one end of the engine's crankshaft 13.Machined into the flex plate 66 is a circular array of circumferentiallyspaced fastener holes 71. As seen in FIG. 3, these fastener holes 71receive therethrough threaded bolts 78 or other fasteners thatthreadably mate with complementary internally threaded female holes inthe engine hub 74 to thereby rigidly couple the flex plate 66 directlyto the engine hub 74 to rotate in unison with the crankshaft 13. Flexplate 66 drivingly connects the damper assembly 26, disconnect device 28and, when desired, the torque converter assembly 16 to the engine's 12crankshaft 13—by way of engine hub 74—such that rotational power istransferable back-and-forth therebetween. In addition to operating totransmit torque produced by the engine 12 to the transmission 16, theflex plate 66 may also function to absorb thrust loads that may begenerated by the torque converter 18 hydrodynamics and/or throughoperation of the disconnect device 28. Projecting radially outward froman outer diameter (OD) edge of the flex plate body is a succession ofgear teeth 73—collectively defining a “starter ring gear”—thatoperatively engage with gear teeth of an engine starter.

A ring-shaped damper plate 68, which sits generally flush against anengine-side surface of the flex plate 66, circumscribed by the starterring gear teeth 73, is fixedly attached via hexagonal bolts 80 or otherfasteners to the pocket plate 60 for common rotation therewith. In anyof the instances in this disclosure where bolts or threaded fastenersare disclosed as a mechanism for connecting two or more components, itshould be recognized that other processes may be employed to join thosecomponents, such as riveting, welding, forming, etc. Damper plate 68 isshown interposed between and, thus, sandwiched by the engine assembly 12and the flex plate 66. The damper plate 68 of FIGS. 2 and 3 is alsoequipped with one or more spring-mass damper systems, also referred toherein as “SDS” and identified as 82 in the drawings. These SDS 82 areshown spaced circumferentially around and positioned proximate to theouter periphery of the damper plate 68.

The SDS 82 mate the damper plate 68 and pocket plate 60 with the flexplate 66 such that the pocket and damper plates 60, 68 are movablyattached to the flex plate 66. In accord with the illustrated example,the damper plate 68 is fabricated with half-cylinder-shaped springreceptacles 75 that are equidistantly spaced about the plate 68 body'scircumference. While it is envisioned that any logically relevant typeof spring element may be employed, the SDS 82 of FIG. 3 each includes ahelical spring terminating at each end thereof with a spring retainer.As best seen in FIG. 3, each SDS 82 is seated within a respective one ofthe spring receptacles 75 such that the length of each helical spring iselongated along the circumference of the plate 68. Defined through thebody of the flex plate 66 are circumferentially spaced spring windows77, each of which receives therethrough a respective one of the SDShelical springs. To this regard, the pocket plate 60 is formed withcircumferentially spaced spring channels 79 that are radially alignedwith the spring windows 77 in the flex plate 77 such that the SDShelical springs are seated within these channels 79, sandwiched betweenthe pocket plate 60 and damper plate 68. When the flex plate 66 rotatesunder the driving power of the engine assembly 12, the spring retainersof each SDS 82 are pressed against respective circumferentially spacedwalls of the spring windows 77, thereby compressing the springs. Thisinteraction can be used to absorb and dampen unwanted torsionalsproduced by the engine 12 during normal, startup, transient and shutdownoperations, as some non-limiting examples.

FIG. 4 provides an enlarged front-view illustration of an alternativeflex plate configuration 166 that supplements or replaces the SDS 82 ofFIGS. 2 and 3 with leaf springs for providing spring-biasedtorsional-damping mechanical engagement between the flex plate 166 and adamper plate, such as damper plate 68 of FIG. 3. The spring elements ofFIG. 4 include numerous diametrically elongated leaf springs 182 thatare machined into or otherwise integrally formed with the flex plate166. These leaf spring 182 are elongated I-shaped bars rigidly attachedat only one end thereof to the flex plate 166. Each damper leaf spring182 includes a fastener eyelet 183 for receiving therethrough a threadedbolt or other fastening means (e.g., hexagonal bolts 80 of FIG. 3) tomovably attach the flex plate 182 to a damper plate and a pocket plate.Defined through the disk-shaped body of the flex plate 166 arecircumferentially spaced spring frames 185, each of which surrounds arespective leaf spring 182. These spring frames 185 have a generallyT-shaped configuration with a crossbar section 187 proximate andelongated along the outer peripheral edge of the plate 166. An elongatedstem section 189 is generally orthogonally oriented with and projectsradially inward from the crossbar section 187. Stem section 189 includesa pair of opposing cam surfaces 191 and 193 that abut a radially inwardportion of the leaf spring 182, when the spring flexes sufficiently tocontact these surfaces, and thereby restricts a flexure motion of theleaf springs 182. In so doing, these cam surfaces 191 and 193 increase aspring rate of the leaf springs 182, e.g., approximately 1000-3000% fromabout 3 Nm/deg to about 80 Nm/deg. In other words, the cam surfaces 191,193 restrict the motion of flexure of the leaf springs 182 toprogressively increase its spring rate. Optionally, the leaf springs 182may be stiffened for out of plane stiffness.

While aspects of the present disclosure have been described in detailwith reference to the illustrated embodiments, those skilled in the artwill recognize that many modifications may be made thereto withoutdeparting from the scope of the present disclosure. The presentdisclosure is not limited to the precise construction and compositionsdisclosed herein; any and all modifications, changes, and variationsapparent from the foregoing descriptions are within the scope of thedisclosure as defined in the appended claims. Moreover, the presentconcepts expressly include any and all combinations and subcombinationsof the preceding elements and features.

What is claimed:
 1. A disconnect clutch for selectively connecting anengine assembly with a torque converter, the engine assembly having anoutput shaft, and the torque converter having input structure to receiveengine torque output via the output shaft, the disconnect clutchcomprising: a pocket plate configured to movably attach to the torqueconverter; the pocket plate including a plurality of pockets; aplurality of engaging elements configured to engage the pockets with theinput structure to thereby lock the pocket plate to the torque converterfor common rotation therewith; a selector plate adjacent the pocketplate and configured to move between an engaged position, whereat theengaging elements shift into engagement between and thereby lock thepocket plate and the input structure, and a disengaged position, whereatthe selector plate shifts the engaging elements out of engagementbetween the pockets and input structure; a flex plate adjacent thepocket plate and configured to attach to the output shaft of the engineassembly for common rotation therewith; a damper plate adjacent the flexplate on the opposite side of the pocket plate, the damper plateattached to the pocket plate for common rotation therewith; and aplurality of spring elements mating the damper plate with the flex platesuch that the damper plate is movably attached to the flex plate.
 2. Thedisconnect clutch of claim 1, wherein the torque converter includes apump housing with a hub projecting therefrom, and wherein the pocketplate is configured to rotatably mount onto the hub of the pump housing.3. The disconnect clutch of claim 2, wherein the hub of the pump housingincludes an annular slot, and wherein the pocket plate includes acentral ring configured to concentrically align with and seat in theannular slot.
 4. The disconnect clutch of claim 1, wherein the outputshaft of the engine assembly includes an engine hub mounted to one endof a crankshaft, and wherein the flex plate includes a plurality offastener holes configured to receive therethrough fasteners that rigidlycouple the flex plate directly to the engine hub.
 5. The disconnectclutch of claim 1, wherein each of the engaging elements includes a pawlrotatably seated within a respective one of the pockets of the pocketplate.
 6. The disconnect clutch of claim 5, wherein the pawls arecircumferentially spaced around the pocket plate, and wherein the inputstructure of the torque converter includes a pump housing withcircumferentially spaced notches, the pawls engaging the pump housing,to thereby lock the pocket plate to the torque converter, by protrudinginto and abutting the notches.
 7. The disconnect clutch of claim 6,wherein the selector plate includes circumferentially spaced windows,and wherein moving the selector plate to the engaged position alignseach of the windows with a respective one of the pockets such that thepawl seated therein projects through the window and into one of thenotches of the pump housing.
 8. The disconnect clutch of claim 7,further comprising a selector ring attached to the selector plate andconfigured to rotate between deactivated and activated positions tothereby move the selector plate between the engaged and disengagedpositions, respectively.
 9. The disconnect clutch of claim 1, whereinthe damper plate includes a plurality of circumferentially spaced springreceptacles, and wherein the spring elements include helical springseach seated within a respective one of the spring receptacles.
 10. Thedisconnect clutch of claim 9, wherein the flex plate includescircumferentially spaced spring windows each receiving therethrough arespective one of the helical springs.
 11. The disconnect clutch ofclaim 10, wherein the pocket plate includes a plurality ofcircumferentially spaced channels, each of the helical springs beingseated within a respective one of the channels, sandwiched between thepocket plate and damper plate.
 12. The disconnect clutch of claim 1,wherein the spring elements include a plurality of diametricallyelongated leaf springs fixedly coupled to the flex plate and movablyattaching the flex plate to the damper plate.
 13. The disconnect clutchof claim 12, wherein the flex plate includes a plurality ofcircumferentially spaced spring frames, and wherein the leaf springs areintegrally formed with the flex plate, each situated within a respectiveone of the spring frames.
 14. The disconnect clutch of claim 13, whereinthe spring frames each includes a pair of opposing cam surfacesconfigured to abut the leaf springs, when flexing, and restrict aflexure motion of the leaf springs and thereby increase a spring rate ofthe leaf springs.
 15. A motor vehicle comprising: a vehicle body with aplurality of drive wheels; an internal combustion engine (ICE) assemblyattached to the vehicle body, the ICE assembly including a crankshaftconfigured to output torque generated by the ICE assembly; a multi-speedtransmission operable to transmit torque output by the ICE assembly toone or more of the drive wheels; a hydrodynamic torque converterselectively connecting the ICE assembly to the multi-speed transmissionto govern the transfer of torque therebetween; and a selectable one wayclutch (SOWC): a pocket plate rotatably attached to an exterior portionof the torque converter, the pocket plate including a plurality ofpockets; a plurality of engaging elements configured to selectivelyengage the pockets with input structure of the torque converter tothereby lock the pocket plate to the torque converter for commonrotation therewith; a selector plate adjacent the pocket plate andconfigured to move between an engaged position, whereat the engagingelements engage the pockets with input structure, and a disengagedposition, whereat the selector plate shifts the engaging elements out ofengagement between the pockets and the input structure such that thepocket plate freewheels on the exterior of the torque converter; a flexplate adjacent the pocket plate and rigidly attached to the crankshaftof the engine assembly for common rotation therewith; a damper plateinterposed between the flex plate and the ICE assembly, the damper plateattached to the pocket plate for common rotation therewith; and aplurality of spring elements mating the damper plate with the flex platesuch that the damper plate and pocket plate are movably attached to theflex plate.
 16. The motor vehicle of claim 15, wherein the torqueconverter includes a pump housing attached to a front cover to enclosetherein an impeller and a turbine, the pump housing including a hubprojecting axially therefrom, and wherein the pocket plate is rotatablymounted onto the hub of the pump housing.
 17. The motor vehicle of claim15, further comprising an engine hub mounted to one end of thecrankshaft, wherein the flex plate includes a plurality of fastenerholes receiving therethrough plural fasteners that rigidly couple theflex plate directly to the engine hub.
 18. The motor vehicle of claim15, wherein each of the engaging elements includes a pawl rotatablyseated within a respective one of the pockets, the pawls beingcircumferentially spaced around the pocket plate, and wherein the inputstructure of the torque converter includes a pump housing withcircumferentially spaced notches, the pawls engaging the pump housing,to thereby lock the pocket plate to the torque converter, by protrudinginto and abutting the notches.
 19. The motor vehicle of claim 18,wherein the selector plate includes circumferentially spaced windows,and wherein moving the selector plate to the engaged position alignseach of the windows with a respective one of the pockets such that thepawl seated therein projects through the window and into one of thenotches of the pump housing.
 20. The motor vehicle of claim 15, whereinthe damper plate includes a plurality of circumferentially spaced springreceptacles, the spring elements including helical springs seated withinthe spring receptacles, and wherein the flex plate includescircumferentially spaced spring windows each receiving therethrough arespective one of the helical springs.